Diagnosis Of Supraventricular Tachycardia Research Articles

Supraventricular Tachycardia

Supraventricular tachycardias (SVTs) comprise a group of usually benign arrhythmias that originate from cardiac tissue at or above the His bundle. SVTs include inappropriate sinus tachycardia, atrial tachycardias (ATs), atrial flutter (AFL), junctional tachycardia, atrioventricular nodal reentrant tachycardia (AVNRT), and forms of accessory pathway–mediated reentrant tachycardias (atrioventricular reentrant tachycardia [AVRT]). Although mostly benign, symptoms can be debilitating, in the form of palpitations, shortness of breath, chest discomfort, dizziness, and/or syncope; rarely, SVTs can result in cardiomyopathy due to incessant arrhythmia. This review covers the epidemiology, diagnosis, management, and classification of SVTs. This review contains 14 figures, 17 tables, and 61 references. Keywords: Supraventricular tachycardia, cardioversion, arrhythmia, atrial flutter, atrial fibrillation, Wolff-Parkinson-White syndrome, MAZE procedure, catheter ablation

Supraventricular tachycardia: current methods of diagnosis and treatment (the focus on updated 2019 European Society of Cardiology clinical practice guidelines for the management of patients with supraventricular tachycardia)

The lecture is devoted to one of the most urgent problems in cardiology – management of patients with paroxysmal supraventricular tachycardia (SVT) in clinical practice. The main principles of the diagnosis of SVT and their electrophysiological mechanisms are outlined. Clinical presentation and ECG diagnosis of different forms of tachycardia are stated. The acute care and long-term treatment of SVT with narrow and wide QRS complex are presented. The methods of treatment and algorhythms of management of patients with SVT are given according to the updated ESC guidelines. The data on antiarrhythmic drugs and their usage are presented, along with the general principles of catheter treatment of tachycardia

Impact of preoperative electrophysiological intervention on occurrence of peri/postoperative supraventricular tachycardia following Fontan surgery

Little is known about the effects of preoperative electrophysiological study (EPS) and catheter ablation (CA) in Fontan surgery candidates with supraventricular tachycardia (SVT). The purpose of this study was to investigate the clinical impact of EPS-guided intervention in Fontan surgery candidates with preceding SVT events. A total of 109 consecutive patients with a history of SVT before Fontan surgery were divided into 3 groups: 44 in whom EPS with CA was attempted (CA group); 21 in whom EPS without CA was attempted (EPS group); and 44 in whom EPS was not performed (N group). The incidence and diagnosis of SVT, acute success rate of CA, and risk factors of peri/postoperative SVT were retrospectively investigated. The total incidence of SVT within 1 year after Fontan surgery was 34% (n = 37), with 91% of cases occurring within 1 month. Among the 71 SVT incidences diagnosed with EPS, 31 were atrioventricular reentrant tachycardias (AVRTs) involving twin atrioventricular nodes, 12 were atrioventricular nodal reentrant tachycardias, 12 were atrial tachycardias, 7 were orthodromic AVRTs via the accessory pathway, 7 were atrial flutters, and 2 werejunctional tachycardias. The acute success rate of CA was 91% (48/53). The rate of peri/postoperative atrioventricular reciprocating SVT was significantly lower in the CA group than in the N or EPS group (11% vs 43% or 43%; P <.05). No/unsuccessful CA significantly increased the risk of peri/postoperative SVT in multivariate analysis (odds ratio 4.43; 95% confidence interval 1.69-11.59). Preoperative CA reduces peri/postoperative SVT occurrence in Fontan surgery candidates at high risk for SVT.

Anterograde His bundle activation during right ventricular overdrive pacing in supraventricular tachycardia.

Differentiation between atrioventricular nodal re-entrant tachycardia (AVNRT), atrioventricular re-entrant tachycardia (AVRT), and atrial tachycardia (AT) is often challenging during electrophysiology studies. This study compared the sensitivity and specificity of identifying anterograde His bundle activation during entrainment with commonly used right ventricular (RV) pacing maneuvers to differentiate between these types of supraventricular tachycardia (SVT). Out of 112 consecutive patients with SVT, 90 (36 males [40%], age 37 ± 16 years) were prospectively studied. After entrainment during RV pacing, atrial response upon cessation of pacing, anterograde His activation during entrainment, stimulus-atrial (SA), ventriculoatrial (VA) intervals, and post-pacing interval minus tachycardia cycle length (PPI-TCL) were determined. Ventricular extrastimulation during tachycardia and para-Hisian pacing were performed. The final diagnosis was AVNRT in 54, AVRT in 33, and AT in 3 patients. Entrainment was achieved in 87(96%) patients. Anterograde His bundle activation predicted AVRT (sensitivity: 62.5%, specificity: 100%). PPI-TCL ≥129ms predicted AVNRT (sensitivity: 83%, specificity: 84%), as did SA-VA value ≥85ms (sensitivity: 91%, specificity: 87%). Atria were advanced during transition zone in 57% of AVRTs. Atrial pre-excitation in response to progressively premature ventricular extrastimuli identified AVRT (sensitivity: 90%, specificity: 85%). Pre-excitation index ≥87ms identified AVNRT (sensitivity: 80%, specificity: 100%). Para-Hisian pacing identified AVRT (sensitivity: 25%, specificity: 100%). RV pacing maneuvers, applied in isolation, can misclassify a significant proportion of SVTs. Identifying anterograde His bundle activation during entrainment can complement other discriminators in differential diagnosis of SVT, with greatest sensitivity in septal and right-sided accessory pathways.

Gender differences in management of patients undergoing catheter ablation of atrioventricular nodal reentry tachycardia

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of supraventricular tachycardia (SVT). Similar to other cardiac tests and interventions, gender bias may influence clinical decision making in providing appropriate care for AVNRT patients. We assessed for gender differences in the diagnosis and management of AVNRT patients who underwent catheter ablation. Patients who underwent catheter ablation for AVNRT were included. We explored the gender difference on various clinical parameters such as the time from SVT symptoms, SVT diagnosis, and first electrophysiology consult to time of catheter ablation. Among 140 patients screened, 116 patients met the inclusion criteria, including 67.2% women. Median time from symptoms onset to SVT diagnosis was 18.5 months (interquartile range [IQR] 4.0-58.5) in women versus 4.0 months (0.75-34.7) in men, P=.005. Once SVT was diagnosed, women took a median of 12.5 months (IQR 3.0-57.0) to proceed with ablation versus 3.0 months (1.0-7.0) for men, P≤.001. It took a longer time from the first electrophysiology consultation to ablation: 54.5 days (20.75-144.75) for women versus 20.5 days (6.0-46.25) for men, P=.008. Overall, it took 60.0 months (IQR 12.8-132.0) for women to have an ablation from initial symptoms onset versus 15 months (IQR 4.6-48.0) for men, P=.001. Prior to ablation, women had 3.78±3.79 (mean ±SD) emergency department visits for SVT versus men 1.52±1.72 and women tried 1.28±0.82 medications versus men 0.76±0.68, P<.001 and .001, respectively. This study demonstrates significant and multifactorial gender-related disparities in AVNRT diagnosis and treatment. Larger studies are needed to confirm these results.

Knowledge of and attitudes to emergency tachyarrhythmia treatment among paramedics and nurses

INTRODUCTION: Supraventricular tachycardia (SVT) is a wide term used to describe tachycardia with atri- al and/or ventricular rates exceeding 100 bpm at rest. The underlying mechanism involves His bundle or tissue lying above. As the diagnosis of SVT is often made in the prehospital settings or in an emergency department, the relevant knowledge of all medical personnel, including paramedics, on the diagnosis and treatment procedures is crucial for the patient’s outcome. It is essential to quickly assess the patient’s clinical condition and make decisions based on both electrocardiographic records and the occurrence of adverse symptoms. Some procedures and pharmacological treatments can be implemented by the paramedic on their own, some require a physician’s supervision. The aim of the study was to assess paramedics’ and nurs- es’ knowledge concerning emergency management in tachycardia. METHODS: The study was conducted in January 2019 in south-western Poland among paramedics and nurses working in the Polish National Emergency Medical System (EMS). All participants received information on the study objectives and voluntarily took part in the questionnaire survey. The questionnaire was developed by the authors and included 22 questions referring to gender, age, work experience, type of work in EMS, number of inhabitants in the workplace area, latest training in advanced life support, adverse events in hemodynamically unstable patients, vagal manoeuvres, European Resuscitation Council 2015 guidelines for narrow and broad complex tachycardia in stable and unstable patients with regular and irregular rhythms, indications for synchronized electrical cardioversion, performing synchronized electrical cardioversion in the past, concerns about cardioversion and self-assessed level of experience in tachyarrhythmia treatment. RESULTS: Overall, 200 paramedics and 50 nurses were asked to participate in the study. The final question- naire return rate was 84.5%. The mean age of the participants equalled as 37.90 ± 11.44 years; 50 (29.59%) were female; the mean work experience was 12.07 ± 10.39 years. The correct treatment in a stable patient with narrow QRS tachyarrhythmia (including vassal manoeuvres and adenosine administration) was pro- posed by 88.17% of the participants. The correct treatment in an unstable patient with broad QRS tachyar- rhythmia was proposed by 84.60% of the participants. Overall, 56.80% indicated correct treatment with a beta-blocker in a stable patient with irregular narrow complex tachyarrhythmia with a duration of over 48 hours; 87.57% knew the role of magnesium sulphate in torsade de pointes treatment. Only 34.91% had conducted electrical cardioversion in the past. According to the subjects, the main problems associated with the procedure of electrical cardioversion were: analgosedation and airway management (52.66%), the risk for sudden cardiac arrest as a result of electrical cardioversion (53.25%), and the risk of a stroke (38.46%). The proper number of electrical cardioversions in unstable patients was proposed by 73.37% of the partic- ipants; 66.86% knew the correct dose of amiodarone when the correct electrical cardioversion sequence does not restore the sinus rhythm and the patient remains unstable. Only 43.79% knew the correct initial biphasic energy for electrical cardioversion in unstable broad complex tachyarrhythmia (120–150 J), while most responders indicated energy up to 120 J. The mean self-assessed level of experience in tachyarrhythmia treatment was 6.00 ± 1.76 in a scale of 0–10, where 0 meant lack of experience and 10 stood for experience ensuring proper performance of the procedure. CONCLUSIONS: The knowledge of Polish paramedics and nurses concerning the emergency treatment of tach- yarrhythmia is unsatisfactory in many aspects. Better undergraduate and postgraduate training on advanced life support guidelines should be recommended.

The relationship between blood glucose and nocturnal supraventricular tachycardia attacks in non-diabetic patients.

Decrease in the blood glucose level may trigger the tachycardia or bradycardia because it has an arrhythmogenic effect on the heart. Our purpose in this study was to investigate whether the blood glucose level has an effect on patients who attended to the hospital with nocturnal supraventricular tachycardia (SVT). We included 151 patients in our study who have SVT history. Plasma glucose levels which were taken during night hours, electrolytes, and 12 lead electrocardiography were evaluated. There were 105 patients without nocturnal SVT attack and 46 patients with nocturnal SVT attack. Patients with nocturnal SVT attack, blood glucose level, potassium, calcium, and hemoglobin levels were significantly lower, hs-CRP was significantly higher, basal cycle length (BCL) was significantly short, and QT interval was significantly longer. It was found that blood glucose (O.R. = 0.904, 95% GA 0.828-0.986, p = 0.023) and potassium levels (O.R. = 0.128, 95% GA 0.029-0.561, p = 0.006) and basal cycle length (BCL) (O.R. 0.988, 95% GA, 0.980-0.996, p = 0.005) values were in independently correlated with nocturnal SVT attacks. The decrease in blood glucose level of the patients who are being followed with SVT diagnosis might trigger the nocturnal SVT attacks.

Abstract 194: The Effect of Obstructive Sleep Apnea on the Outcomes of Patients with Supraventricular Tachycardia

Background: The obesity epidemic has become a major public health issue with repercussion through all the spectrum of cardiovascular disease. Obesity-associated pathologies like obstructive sleep apnea (OSA) have also emerged. There have been some studies associating OSA with cardiovascular disease, but the impact on outcomes is largely unknown. Purpose: evaluate the impact of OSA after adjustment for obesity on the outcomes of patients with supraventricular tachycardia (SVT). Methods: A retrospective analysis using the 2014 Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample (NIS) was performed. Patients between the ages of 18 and 65 with a primary diagnosis of SVT as well as secondary diagnosis of OSA. The primary outcome was in-hospital mortality. The secondary outcomes were length of stay, cardiogenic shock, use of mechanical ventilation, acute kidney injury requiring dialysis (AKID), cost of stay, rate of direct current cardioversion (DCCV), rate of ablation, hemorrhage requiring transfusion (HRT), cardiac arrest and heart failure (HF) exacerbation. Multivariate regression analyses after adjustment for age, race, insurance, hospital location and obesity was done. Analysis was performed using Stata 15 IC. Results: 7,690 patients with a primary diagnosis of SVT and secondary diagnosis of OSA were identified. 67% of this population were female and mean age was 65 years. Patients with OSA and SVT had decreased odds of death (OR 0.53 p&lt;0.001) as well as decreased odds of HRT (OR 0.59 p&lt; 0.001) and development of cardiogenic shock (OR 0.51 p=0.03). Also, a non-statically significant trend towards increased AKID (OR 1.11 p=0.71), along with decreased odds of cardiac arrest (OR 0.80 p= 0.34) and stroke (OR 0.82 p=0.72) was seen. There was also increased rate of heart failure exacerbation (OR 1.42 p&lt;0.001) in patients with OSA hospitalized for SVT. Risk of cardiac arrest (OR 0.80 p=0.34) and stroke (OR 0.82 p=0.72) exhibit a non-statically significant decreased in odds. Length of stay was showed to be less (1.3 days p&lt;0.001) in the OSA group cohort. Conclusion: Prior studies have showed decreased mortality in OSA patients with acute myocardial infarction. This retrospective analysis demonstrated that patients with OSA had decreased mortality when hospitalized for SVT. Nevertheless, patients had increased risk of HF exacerbation. Further studies are needed to clarify the full extent of this relationship.

CATECHOLAMINE-INDUCED CARDIOMYOPATHY IN THE POSTPARTUM PATIENT

There are several conditions that can cause cardiomyopathy (CM) in the postpartum period. Diagnosis of the etiology of CM can have important implications in management and prognosis of these patients. A 30 year old female with recent diagnosis of supraventricular tachycardia (SVT) presented with

First experience with zero-fluoroscopic ablation for supraventricular tachycardias using a novel impedance and magnetic-field-based mapping system

AimsZero- and near-zero-fluoroscopic ablation techniques reduce the harmful effects of ionizing radiation during invasive electrophysiology procedures. We aimed to test the feasibility and safety of a zero-fluoroscopic strategy using a novel integrated magnetic and impedance-based electroanatomical mapping system for radiofrequency ablation (RFA) of supraventricular tachycardias (SVTs).MethodsWe retrospectively studied 92 consecutive patients undergoing electrophysiology studies with/without RFA for supraventricular tachycardia (SVT) performed by a single operator at a single center. The first 42 (Group 1) underwent a conventional fluoroscopic-guided approach and the second 50 (Group 2) underwent a zero-fluoroscopic approach using the Ensite Precision™ 3-D magnetic and impedance-based mapping system (Abbott Inc).ResultsGroup 1 comprised 14 AV-nodal re-entrant tachycardia (AVNRT), 12 typical atrial flutter, 4 accessory pathway (AP), 2 atrial tachycardia (AT), and 9 diagnostic EP studies (EPS). Group 2 comprised 16 AVNRT, 17 atrial flutter, 6 AP, 3 AT, 2 AV-nodal ablations, and 7 EPS. A complete zero-fluoroscopic approach was achieved in 94% of Group 2 patients. All procedures were acutely successful, and no complications occurred. There was a significant reduction in fluoroscopy dose, dose area product, and time (p < 0.0001, for all), with no difference in procedure times. Ablation time for typical atrial flutter was shorter in Group 2 (p = 0.006).ConclusionsA zero-fluoroscopic strategy for diagnosis and treatment of SVTs using this novel 3D-electroanatomical mapping system is feasible in majority of patients, is safe, reduces ionizing radiation exposure, and does not compromise procedural times, success rates, or complication rates.

Antenatal antiarrhythmic treatment for fetal tachyarrhythmias: a study protocol for a prospective multicentre trial

IntroductionSeveral retrospective or single-centre studies demonstrated the efficacy of transplacental treatment of fetal tachyarrhythmias. Our retrospective nationwide survey showed that the fetal therapy will be successful at an overall rate...

Postnatal Outcomes of Fetal Supraventricular Tachycardia: a Multicenter Study.

Supraventricular tachycardia (SVT), the most common fetal tachycardia, can be difficult to manage in utero. We sought to better understand predictors of the postnatal clinical course in neonates who experienced fetal SVT. We hypothesized that fetuses with hydrops or those with refractory SVT (failure of first-line SVT therapy) are more likely to experience postnatal SVT. This was a retrospective multicenter cohort study of subjects diagnosed with fetal SVT between 2006 and 2014. Fetuses with structural heart disease were excluded. Descriptive comparative statistics and univariate analysis with logistic regression were utilized to determine factors that most strongly predicted postnatal SVT and preterm delivery. The cohort consisted of 103 subjects. Refractory SVT was found in 37% (N=38) of the cohort with this group more likely to be delivered prematurely (median=36 vs. 37.5weeks, p=0.04). Refractory SVT did not increase the risk of postnatal SVT (p=0.09). Postnatal SVT was seen in 61% (N=63). Of those, 68% (N=43) had postnatal SVT at ≤2days of age. Postnatal SVT was associated with a later fetal SVT diagnosis (median=30 vs. 27.5weeks, p=0.006). We found a strong correlation between postnatal SVT and later gestational age at fetal SVT diagnosis. Subjects with refractory SVT or hydrops did not have a higher risk of postnatal SVT. We propose strong consideration for term delivery in the absence of significant clinical compromise. Further studies to assess whether outcomes vary for preterm delivery versus expectant management in those with refractory SVT should be performed.

Ventricular arrhythmias and sudden cardiac death

### Key points There are 50–100 unexpected, sudden cardiac deaths (SCDs) per 100 000 population per year in Europe and USA, categorized by symptom onset to cardiac arrest time of <1 h.1 Despite the decline in coronary artery disease mortality and advancements in resuscitation services, survival from these events remains low. Unfortunately, they often occur outside the hospital environment and are associated with a survival rate of <10%. The majority occur in adults over 35 yr of age and at least half of these events can be attributed to ventricular arrhythmias, although the true incidence is unknown due to inevitable degeneration to asystole if unwitnessed. These arrhythmias may be the presenting complaint in the emergency department and may feature throughout the perioperative period, including at preoperative assessment, during surgery and in the recovery phase, for example in intensive care. They may also be the direct target of therapy in the case of electrophysiological catheter ablation and implantable cardioverter defibrillators (ICDs). They are more frequent and carry greater risks in patients with structural heart disease, but younger patients with ion-channel abnormalities can also be susceptible.2 This review classifies the causes and significance of ventricular arrhythmias based on the presence or absence of structural heart disease and provides a simple system to aid confident distinction from supraventricular arrhythmias. …

Validation of Standard and New Criteria for the Differential Diagnosis of Narrow QRS Tachycardia in Children and Adolescents.

To establish an appropriate treatment strategy and determine if ablation is indicated for patients with narrow QRS complex supraventricular tachycardia (SVT), analysis of a standard 12-lead electrocardiogram (ECG) is required, which can differentiate between the 2 most common mechanisms underlying SVT: atrioventricular nodal reentry tachycardia (AVNRT) and orthodromic atrioventricular reentry tachycardia (OAVRT). Recently, new, highly accurate electrocardiographic criteria for the differential diagnosis of SVT in adults were proposed; however, those criteria have not yet been validated in a pediatric population.All ECGs were recorded during invasive electrophysiology study of pediatric patients (n = 212; age: 13.2 ± 3.5, range: 1–18; girls: 48%). We assessed the diagnostic value of the 2 new and 7 standard criteria for differentiating AVNRT from OAVRT in a pediatric population.Two of the standard criteria were found significantly more often in ECGs from the OAVRT group than from the AVNRT group (retrograde P waves [63% vs 11%, P < 0.001] and ST-segment depression in the II, III, aVF, V1–V6 leads [42% vs 27%; P < 0.05]), whereas 1 standard criterion was found significantly more often in ECGs from the AVNRT group than from the OAVRT group (pseudo r′ wave in V1 lead [39% vs 10%, P < 0.001]). The remaining 6 criteria did not reach statistical significance for differentiating SVT, and the accuracy of prediction did not exceed 70%. Based on these results, a multivariable decision rule to evaluate differential diagnosis of SVT was performed.These results indicate that both the standard and new electrocardiographic criteria for discriminating between AVNRT and OAVRT have lower diagnostic values in children and adolescents than in adults. A decision model based on 5 simple clinical and ECG parameters may predict a final diagnosis with better accuracy.

Abstract 15866: Incidence and Severity of Left Atrial Scar in Older Patients With and Without Atrial Fibrillation

Background: Atrial fibrosis or scar is considered a substrate change related to atrial fibrillation (AF); by slowing conduction and increasing heterogeneity it could provide a substrate for AF. However, it is still not known whether AF causes the profibrotic changes in the left atrial wall or simply facilitates the manifestation of an existing aging-related structural remodeling in older patients. We examined scar prevalence and severity in patients aged ≥ 75 years with and without AF to address this question. Method: Five hundred seventy one patients undergoing radio-frequency catheter ablation for AF or supraventricular tachycardia (SVT) were included in this prospective analysis and classified into 2 groups; group 1: patients with AF (n=308, 62% male, median 77.8 (75 to 91) years, 46% paroxysmal and 64% persistent AF) and group 2: patients with diagnosis of SVT (n=263, 56% male, median 80 (75 to 88) years). Left atrial (LA) scarring was determined by three-Dimensional (3D) voltage mapping. Scar was defined as an area with a bipolar voltage amplitude ≤ 0.05 mV, indistinguishable from noise. The degree of scar was described as a percentage of the LA area (mild &lt;20%, moderate 20-60%, and severe &gt;60%) involved. Results: Age and gender distribution was similar in both groups. Left atrial scar was detected in 172 (56%) patients in group 1 and 134 (51%) in group 2 (p=0.24). After adjusting for age and gender in multivariable logistic model, diagnosis of AF or SVT did not show to have any association with the incidence of scar (p=0.22). Based on the 3D mapping, 52(30%) patients were classified as having mild LA scarring, 88(51%) moderate scar and 32(19%) with severe scar in group 1. Distribution of scar severity in group 2 was: mild 50(37%), moderate 67(50%), and severe in 17(13%), which was similar to that of AF patients (p=0.248). Conclusion: Similar prevalence and distribution of severity of the left atrial scarring in elderly patients with and without atrial fibrillation suggest age-dependent substrate remodeling to be the major contributor of scar formation. Our results indicate that scar could facilitate atrial fibrillation in predisposed subjects only.

Abstract 18654: Expert Adjudication of Device Electrograms: Is an Atrial Channel More Important than Gray Hair?

Background: The diagnosis of a tachycardia from ICD recordings ultimately depends upon analysis of captured electrograms (EGMs). While atrial EGM may improve tachycardia discrimination, the degree of benefit has not been evaluated in medical professionals with different level of expertise. Methods: Expert-adjudicated supraventricular tachycardia (SVT) and ventricular tachycardia (VT) EGMs from the RATE Registry were given to EP Specialists (EPS), EP Fellows (EPF), and Nurse Practitioners or Physician Assistants (NPPA). Each participant diagnosed 112 EGMs (61 VTs, 51 SVTs) as SVT, VT, or Uncertain in two stages. First, participants made diagnosis based on ventricular EGM (VEGM) alone (Atrial Channel covered). Then the EGMs were re-randomized with atrial EGM exposed and diagnosis was made again. The accuracy of diagnosis by EPS, EPF, and NPPA in the use of VEGM alone vs dual-chamber EGM was assessed. Results: Fifteen participants (5 in each group) completed diagnosis. All 3 groups significantly improved diagnosis accuracy (&gt;20% for VTs, &gt;15% for SVTs, all p values &lt; 0.02) when dual-chamber EGM was provided. EPS diagnosed VTs more accurately than NPPA (VEGM: 73.1±7.6% vs 56.1±14.1%, p = 0.03; dual-chamber EGM: 98.0±2.7% vs 80.3±7.4%, p = 0.001). EPF diagnosed VTs better than NPPA but worse than EPS (not statistically significant). There was no significant intergroup difference in SVT diagnosis. Conclusion: These results suggest that atrial EGMs help rhythm discrimination at all levels of expertise. However, experience seems to improve diagnosis accuracy with and w/o atrial EGM.

Simplified Automated Right Ventricular Overdrive Pacing for Rapid Diagnosis of Supraventricular Tachycardia

Objectives: The purpose of this study was to prospectively evaluate the feasibility and diagnostic value of right ventricular overdrive pacing (RVOP) during supraventricular tachycardia (SVT) using a 2-catheter approach with automatic pacing from the right ventricular inflow (RVIT) and outflow tract (RVOT). Methods: One hundred and thirty-six consecutive patients (with 138 arrhythmias, mean age 36 ± 20 years, range 4-95) were enrolled in this study. Only coronary sinus and ablation catheters were used. RVOP was delivered from RVIT and then from RVOT. Each attempt consisted of 10 synchronized beats delivered at a cycle length of 10-40 ms longer than the tachycardia cycle length. Results: RVOP was sufficient to confirm the transition zone within the first 9 beats in the majority of SVTs. Atrial perturbation (acceleration, delayed) in the transition zone was detected in all patients with orthodromic atrioventricular (AV) reentry. Patients with typical AV nodal reentry, atypical AV nodal reentry and atrial tachycardia did not show atrial timing perturbation during fusion complexes of RVOP. Conclusions: Synchronized RVOP from RVIT or RVOT is an easy and accurate method for the quick and reliable differential diagnosis of SVT in various clinical settings, particularly when only a limited number of catheters are used.

Prehospital management of supraventricular tachycardia in Victoria, Australia: epidemiology and effectiveness of therapies.

The present study examined patient demographics, characteristics and the effectiveness of current prehospital supraventricular tachycardia (SVT) management by ambulance paramedics in Victoria, Australia. We conducted a retrospective study of all Victorian patients attended by paramedics between 14 February 2012 and 13 February 2013, where SVT was the initial or final diagnosis. Patients were excluded if SVT was not captured on ECG, incomplete data were recorded, or SVT began after initial assessment. Data were extracted from the VACIS(®) clinical data warehouse. Accuracy of paramedic SVT diagnosis was examined. Nine hundred and thirty-three patients were enrolled, including 882 (94.5%) adults and 564 (60.5%) women. Mean adult and paediatric (<18 years) patient ages were 57.5 (SD 18.1) and 10.0 (SD 4.5) years, respectively. Median ambulance response time was 11.0 (IQR 8.0) min. Paramedics correctly identified SVT in 119/123 (96.7%, 95% CI: 91.5, 99.0) of adult ECG strips examined. There were 273/882 (31.0%) patients who spontaneously reverted while in paramedic care. Valsalva manoeuvre was undertaken by 212/882 (24.0%) patients and reverted the SVT in 99/358 (27.7%) attempts. Verapamil was administered to 38/882 (4.3%) patients and reverted 33 (86.8%). Aramine was administered to 43/882 (4.9%) patients and 35 reverted following administration (81.4%). Synchronised cardioversion (70 J) reverted four patients at first attempt. Ultimately, 438 (49.7%) patients remained in SVT on arrival at hospital. Patient characteristics associated with SVT are more likely to be middle-aged women with a history of hypertension and hypercholesterolaemia. Therapies were underutilised leading to reduced clinical guideline effectiveness. Where therapies were instigated, reversion rates are greater than previously reported.

Comparison of the “Real-life” Diagnostic Value of Two Recently Published Electrocardiogram Methods for the Differential Diagnosis of Wide QRS Complex Tachycardias

The diagnostic values of the aVR lead or "Vereckei algorithm," and the lead II R-wave peak time (RWPT) criterion, recently devised for the differential diagnosis of wide QRS complex tachycardias (WCTs), were compared. A total of 212 WCTs (142 ventricular tachycardias [VTs], 62 supraventricular tachycardias [SVT], and eight preexcitation SVTs) from 145 patients with proven electrophysiologic diagnoses were retrospectively analyzed by seven examiners blinded to the electrophysiologic diagnoses. The overall test accuracy of the Vereckei algorithm was superior to that of the RWPT criterion (84.3% vs. 79.6%; p = 0.0003). The sensitivity of the Vereckei algorithm for VT diagnosis was greater than that of RWPT criterion (92.4% vs. 79.1%; p < 0.0001). The negative predictive value (NPV) for the Vereckei algorithm was also greater (77.8%; 95% confidence interval [CI] = 73.6% to 82.1%) than that of the RWPT criterion (61.6%; 95% CI = 57.6% to 65.6%). The specificity of the Vereckei algorithm was lower than that of the RWPT criterion (64.7% vs. 80.9%; p < 0.0001). The positive predictive value (PPV) was also lower for the Vereckei algorithm (86.4%; 95% CI = 84.4% to 88.4%) than for the RWPT criterion (90.9%; 95% CI = 89.1% to 92.8%). Incorrect diagnoses made by the Vereckei algorithm were mainly due to misdiagnosis of SVT as VT (65.7% of cases), and those made by the RWPT criterion were due to the more dangerous misdiagnosis of VT as SVT (72.5% of cases). The Vereckei algorithm was superior in overall test accuracy, sensitivity, and NPV for VT diagnosis and inferior in specificity and PPV to the RWPT criterion. All of these parameters were lower in "real life" than those reported by the original authors for each of the particular electrocardiographic methods.

New considerations for optimizing single diagnostic pacing maneuvers for supraventricular tachycardia

The diagnosis of supraventricular tachycardia (SVT) has dramatically evolved in the last 4 decades. Prior to the early 1970s, it was possible to classify SVTs only into atrial fibrillation, atrial flutter, or paroxysmal SVT. In contrast, with the consistent improvement in electrophysiology (EP) technology, we can nowadays better distinguish between specific SVT mechanisms and sites of origin by using programmed electrical stimulations, recording intracardiac electrograms and surface electrocardiograms, and even establishing detailed activation maps.